Pneumatic gas inlet valve with adjustable stopper

Abstract

The present invention relates to a gas inlet valve (1) for controlled fluid entry into a vacuum process chamber, the gas inlet valve (1) comprising a gas conduction unit (2) having a sealing surface (24) within an internal volume (23), a regulating device (3) with an adjusting unit (31) that projects into the internal volume (23) and is adjustably supported along an adjustment axis outside the gas conduction unit (2) within the regulating device (3), and a flexible sealing element (25) fixed to the gas conduction unit (2) and the adjusting unit (31) and sealing the regulating device (3) from the internal volume (23). The regulating device (3) has a preload element (34) cooperating with the adjusting unit (31) and positioned to provide a preload force that biases a valve plate (32) in a closing direction (S). The adjusting device (3) has a pneumatic drive cylinder (35) with at least one piston (36a) connected to the adjusting unit (31), and by applying pressure to the drive cylinder (35), an opening force can be generated in the opening direction (O) that counteracts the preload force. The adjusting device (3) has a limiting element (37) that provides a stop point (38) that limits the adjustability of the adjusting unit (31) along the adjustment axis (V) in the opening direction (O). The limiting element (37) is shaped and supported such that the position of the stop point (38) along the adjustment axis (V) can be changed by operating the limiting element (37), and the position of the stop point (38) defines the maximum valve opening.

Description

[Technical Field]

[0001] The present invention relates to a gas inlet valve for admitting fluid into a vacuum process chamber.

[0002] Background of the Invention Such vacuum process chambers are used in integrated circuit (IC) manufacturing, semiconductor manufacturing, flat panel manufacturing, or substrate manufacturing, where the vacuum chamber is evacuated and then flushed with process gas for at least some of the process steps. The manufacturing must be carried out in a protected atmosphere, as free as possible from contaminant particles. In this case, evacuation is achieved using a vacuum valve connecting the vacuum process chamber to a vacuum pump, but the design and technical requirements of the vacuum valve differ from those of a gas inlet valve.

[0003] Furthermore, such a vacuum chamber has at least one or two vacuum chamber openings through which the elements to be processed can be guided into and / or out of the vacuum chamber. For example, in manufacturing facilities for semiconductor wafers or liquid crystal substrates, highly sensitive semiconductor or liquid crystal elements pass successively through multiple vacuum process chambers, where they are each processed by one processing device.

[0004] Here, the component is placed on support pins extended from a lift system, for example by a robot, and the support pins are lowered to place the component on a support, for example a potential plate (chuck). The robot arm supporting the component is then typically extended from the chamber. The pins can be lowered after the component is placed, so that they are separated from the component, i.e., no contact occurs between the pins and the component. After the robot arm is retracted and the chamber is closed, the chamber is typically evacuated and then filled with process gas, so that component processing can begin.

[0005] Gas inlet valves are specifically designed for defined open-loop or closed-loop control of gas flow rates, for example in pipe systems between a vacuum process chamber (or transfer chamber) and a gas source, atmosphere, or another vacuum process chamber. The opening cross-section of such gas inlet valves is usually smaller than that of a vacuum valve.

[0006] Depending on the application, the gas inlet valve can be used not only to completely open or close the opening, but also for open-loop or closed-loop control of the flow rate by continuously adjusting the opening cross section between an open position and an airtight closed position.

[0007] When a process gas is introduced into a vacuum chamber, it is extremely important to minimize fluid-technical effects in the chamber and to quickly and accurately fill the chamber. For example, a specified amount or volume of a specified process gas must be introduced into the chamber with each opening cycle of a gas inlet valve. For this purpose, on the one hand, rapid valve operation is desirable, and on the other hand, accurate adjustment of the valve opening cross section provided in this case is desirable.

[0008] Problem to be solved by the invention SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an improved gas inlet valve for a vacuum process chamber.

[0009] In particular, the challenge is to provide rapid and in this case continuous accurate flushing of a vacuum process chamber equipped with a gas inlet valve with a process gas.

[0010] Another object of the present invention relates to providing a defined open cross section over an extended period of time.

[0011] Another challenge is to provide a gas admission valve that provides a specified flow coefficient, particularly for a particular process fluid.

[0012] Summary of the Invention The present invention relates to a gas inlet valve having a pneumatic drive for controlled opening of the valve. The gas inlet valve has a return element, in particular a spring, which presses the valve plate of the valve against the valve seat and thus blocks the flow path for the fluid through the valve. The pneumatic drive can be used to generate a counter force that counteracts the return force generated by the return element and thus opens the valve.

[0013] A fluid is understood in the context of the present invention to mean at least one gas, a gas mixture, a liquid, a precursor-containing gas or a gas-liquid mixture. The fluid may in particular be a process gas or a precursor gas.

[0014] The valve plate and / or valve seat (sealing surface) may have a sealing ring that is compressed in the closed position due to the preload of the return element, ensuring that the gas inlet can be tightly separated from the gas outlet.

[0015] Stops are provided to define the stroke of the valve, i.e., the range over which the valve plate is adjusted during the opening process. This allows a relatively rapid opening movement of the valve plate (compared to mechatronic drives, for example, with electric motors) to be achieved solely by supplying pneumatic pressure to the drive, and also allows the opening movement to be limited accordingly. This means that a defined flow rate per time unit can be achieved solely by applying pressure to the pneumatic drive.

[0016] Furthermore, by open-loop controlling the duration of pressure application, the amount of fluid flowing through the valve into, for example, a vacuum chamber can be adjusted relative to the valve opening cycle.

[0017] Furthermore, the stopper of the gas inlet valve is formed so that the stopper point limits the adjustability of the valve plate in the opening direction along a linear adjustment axis, and the position of the stopper point can be moved along the adjustment axis by operating the stopper.

[0018] The stop point therefore defines the maximum valve opening, in particular the stroke of the valve plate, i.e. the distance between the valve plate and the valve seat, when pressure is applied to the pneumatic drive, so that the valve stroke can be adjusted accordingly by moving the stop point.

[0019] Accordingly, the present invention relates to a gas inlet valve for controlled entry or flow of a fluid into a vacuum process chamber, the gas inlet valve comprising a gas flow unit having a gas inlet, a gas outlet, and an interior volume, the interior volume connecting the gas inlet and the gas outlet, and the gas flow unit having a sealing surface within the interior volume.

[0020] The gas inlet valve further comprises a regulating device with an adjusting unit, the regulating unit extending into the internal volume and being adjustably supported along an adjusting axis outside the gas flow unit in the regulating device, and a valve plate arranged in the internal volume, which can be moved by the adjusting device in a closing direction to a closed position in which the valve plate rests on a sealing surface and thus prevents gas from passing through, and in an opening direction to an open position in which the valve plate is separated from the sealing surface and allows gas to pass through.

[0021] The adjusting device further comprises a pneumatic drive cylinder with at least one piston, which is connected to the adjusting unit, and by applying pressure to the drive cylinder or piston, at least one opening force in the opening direction can be generated. In particular, the pneumatic drive cylinder can be configured so that by changing the pressure application (e.g. on the opposite side of the piston), a closing force in the closing direction can be generated. The respective pressure application can be generated, for example, by means of at least one compressed air outlet projecting into or embodied by the drive cylinder. The compressed air outlet is in particular connected to a pneumatic unit or a pneumatic valve.

[0022] The valve further comprises a flexible sealing element, which is fixed to the gas flow unit and the regulating unit and separates or seals the regulating device from the internal volume, and which is in particular configured as a metal-containing diaphragm.

[0023] According to the invention, the adjusting device has a limiting element providing a stop point that limits the adjustability of the adjusting unit along the adjustment axis in the opening direction, the limiting element being shaped and supported in such a way that by manipulating the limiting element the position of the stop point can be changed along the adjustment axis and the position of the stop point determines the maximum valve opening.

[0024] The position of the stop point therefore also defines, inter alia, the open position of the valve.

[0025] In this way, operating the limiting element results in an adjustment of the stop point along the adjustment axis. This adjustability is particularly advantageous because valves and their (mechanical and movable) components can have tolerances regarding their dimensions and / or their support due to manufacturing, and therefore (identically) manufactured valves can have, for example, different valve strokes (and maximum valve opening cross sections). The valve stroke corresponds, in particular, to the distance traveled when the valve plate is adjusted from the maximum opening position to the closed position (or in the opposite direction). The adjustability of the stop point therefore provides a calibration variable for the gas inlet valve, i.e., an adjustment of the valve stroke or maximum valve opening, so that each valve manufactured according to this calibration variable has the same flow characteristics, in particular the same valve stroke.

[0026] Valve calibration can be performed in an automated manner. For example, the flow rate through the valve can be measured, preferably in the open position, and the flow rate through the valve can then be adjusted toward a target value by setting or adjusting the position of the stop point. Alternatively, the dynamic pressure can be measured upstream of the valve to determine the flow coefficient (Cv). The pressure loss through the valve can then be measured.

[0027] In one embodiment, the adjusting device can have a preload element, in particular one or more springs or elastic elements, arranged to provide a preload force that urges the valve plate in the closing direction and cooperating with the adjusting unit, the preload element being present in a correspondingly preloaded state, in particular in the open position of the valve.

[0028] By applying pressure to the drive cylinder, an opening force can be generated in the opening direction, which acts against the preload force. In particular, the preload element can be operatively connected to the at least one piston.

[0029] The gas inlet valve according to the invention combines the advantage that the valve is opened relatively quickly and with high precision by means of a pneumatic actuating cylinder with the possibility of flexible adjustment of the degree of valve opening that can thereby be provided, for example depending on the fluid flowing through it.

[0030] In one embodiment, the gas inlet valve can have an open-loop controllable drive device, which can be connected or coupled to a limiting element such that the position of the stop point can be changed by the drive device.

[0031] The drive device can be configured in particular as an electric motor, in particular as a servomotor or step motor, as a piezo element or as an actuator based on magnetic bearing principles (for example PM linear magnets).

[0032] The connection of the limiting element with the drive allows in particular open-loop controlled and / or automatic operation of the limiting element and thus corresponding open-loop controlled and / or automatic adjustment of the position of the stop point.

[0033] In one embodiment, the gas inlet valve may have a control processing unit configured to control at least the driver.

[0034] In one embodiment, the control processing unit may have an adjustment function for adjusting the position of the stopper point, wherein the adjustment function is configured in that embodiment to perform the steps of processing reference information (e.g., target pressure, target temperature, target flow rate, etc.), processing actual information (e.g., actual pressure, actual temperature, actual flow rate, density and / or composition of the fluid, etc.), comparing the reference information with the actual information, deriving adjustment information based on the comparison, and adjusting the position of the stopper point, particularly automatically, based on the adjustment information.

[0035] The automatic adjustment of the position of the stop point can be carried out, for example, using a closed-loop control, in which case the adjustment function can be continuously performed and the position of the stop point is changed until, based on the adjustment information from the comparison of the reference information and the actual information, it is deemed that no further manipulation of the limiting element is necessary.

[0036] In one embodiment, the actual information can include information about fluid properties, in particular about the composition, type, or variety of the fluid, and the reference information can provide a correlation of fluid properties with the respective positions of the stop points. This arrangement allows, for example, automatic adjustment of the opening position depending on the fluid used, and also allows for automatically controlled provision of a desired flow rate for each fluid. The information about the fluid properties can be provided, for example, by a user.

[0037] In one embodiment, the reference information may include information regarding a target pressure of the fluid, and the actual information may provide the current fluid pressure, particularly in this case where the gas inlet valve has a pressure sensor that determines the fluid pressure.

[0038] According to one embodiment, the reference information may include information regarding the target temperature of the fluid, and the actual information may provide the fluid temperature at that time, particularly in this case the gas inlet valve has a temperature sensor that determines the fluid temperature.

[0039] In one embodiment, the reference information may include information regarding a target flow coefficient for the fluid, and the actual information may provide the current fluid flow coefficient, particularly in this case where the gas inlet valve has a flow measurement unit that determines the fluid flow coefficient.

[0040] According to one embodiment, the reference information may comprise information regarding a target flow coefficient, and the actual information may indicate or provide the density and / or temperature or differential pressure of the fluid, in particular in this case the fluid flow coefficient for the fluid may be derived as actual information using the density and / or temperature of the fluid and / or using the differential pressure.

[0041] The flow coefficient is a measure of the amount of flow that can be achieved through a valve, in particular a fluid (liquid or gas), which can also be interpreted as the effective cross-sectional area.

[0042] The differential pressure corresponds in particular to the pressure difference between the gas inlet and the gas outlet. The gas inlet valve can in particular have a corresponding pressure sensor for determining the differential pressure.

[0043] In one embodiment, the control processing unit may have a compensation function for compensating for position drift from the target position, the compensation function being configured to perform the steps of checking for the presence of position drift, determining or deriving characteristics of the position drift, in particular magnitude and / or direction (if position drift exists), and adjusting, in particular changing, the position of the stop point so as to provide the target position in the open position, when the compensation function is executed.

[0044] The position drift may be a position deviation of the valve plate in the open position or at the stop point, in particular relative to a target position of the valve plate or the stop point, respectively.

[0045] Checking for the presence of a position drift or determining the characteristics of the position drift can be done, inter alia, by position or flow measurement, or by determining the temperature of the gas inlet valve, or based on the number of opening cycles performed with the gas inlet valve.

[0046] For example, it may be known from experience that a valve will have a certain drift, e.g., misalignment due to valve plate wear or seal wear, after a certain number of opening and closing cycles, and then, based on this information, a compensatory follow-up adjustment of the stop point can be made in continuous or discrete steps, e.g., only after a certain number of cycles.

[0047] According to another example, the drift characteristic may be predetermined or known depending on the thermal state of the valve, i.e., the current temperature of the valve, and a corresponding adjustment of the stop point can then be made to counteract the drift.

[0048] Furthermore, the operating method according to the invention makes it possible to compensate for drifts, for example due to wear, as well as narrowing of the flow cross section, for example due to deposits caused by process gases (especially precursors).

[0049] Furthermore, in order to provide a constant gas introduction into the processing volume, compensation of the flow rate during the gas inflow can be carried out by adjusting the stop point, which can be advantageous due to the pressure drop that occurs in the upstream reservoir.

[0050] In one embodiment of the gas inlet valve, the pneumatic drive cylinder can have separate pistons defining respective drive internal volumes, which can be connected to respective compressed air passages that can be arranged such that pressure applied to the drive internal volumes through the compressed air passages causes the pistons to be adjustable in an opening direction, thereby moving the valve plate to an open position.

[0051] In one embodiment of the gas inlet valve, the sealing surface, the valve plate and the sealing element may have a circular cross section, in which case the internal volume is at least partially cylindrical and the sealing surface is formed by a step in the internal volume.

[0052] The cylindrical shape of the internal volume is formed in particular by the gas flow unit as the outer surface and the sealing element as the bottom surface, whereby the gas inlet and the gas outlet have free access to the internal volume via the outer surface, which means that the gas inlet and the gas outlet can each penetrate through the outer surface.

[0053] In particular, the plate divides the internal volume into a first partial volume and a second partial volume in the closed position, with the gas inlet having free access to the first partial volume and the gas outlet having free access to the second partial volume.

[0054] The gas outlet, in an arrangement associated with a vacuum chamber, in particular has free access to the vacuum process chamber, and the gas inlet in particular has free access to a process gas source.

[0055] Other advantages of the present invention will become apparent from the detailed description and drawings. [Brief explanation of the drawings]

[0056] [Figure 1] 1 is a cross-sectional view showing an embodiment of a gas inlet valve according to the present invention. [Figure 2] 2 is a cross-sectional view of the gas inlet valve of FIG. 1 according to the present invention, rotated relative to FIG. 1 about a vertical axis; [Figure 3] FIG. 10 is a detailed view of the internal volume of the gas inlet valve.

[0057] Detailed Description of the Drawings 1 and 2 show an embodiment of a gas inlet valve 1 according to the invention. In Fig. 1, the valve is shown rotated by 90° about the adjustment axis V relative to the illustration in Fig. 2. The gas inlet valve 1 comprises a gas conduction unit 2, which further comprises a gas inlet 21, a gas outlet 22 and an internal volume 23, where the internal volume 23 has free access to the gas inlet 21 and the gas outlet 22 or connects the gas inlet 21 and the gas outlet 22. The gas conduction unit 2 comprises a sealing surface 24 in the internal volume 23.

[0058] The gas inlet valve 1 further comprises a regulating device 3 with a regulating unit 31 and a valve plate 32, where the regulating unit 31 projects into the internal volume 23 and is adjustably supported in the regulating device 3 outside the gas-passing unit 2. The valve plate 32 is arranged in the internal volume 23 and can be moved by the regulating device 3 into a closed position in which the plate 32 rests against the sealing surface 24 and thus prevents gas from passing through. The regulating device 3 can also move the plate into an open position in which the plate 32 is spaced from the sealing surface 24 and thus allows gas to pass through.

[0059] The adjusting device 3 further comprises a preload or return element 34 formed as a spring, which is arranged in a preloaded state in the adjusting device 3 so that the spring 34 exerts a force in the direction towards the valve seat and presses the adjusting unit 31 or the valve plate 32 against the sealing surface 24, i.e. in the closing direction S.

[0060] Due to the preload in one or more springs, the plate 32 is pressed against the sealing surface 24 in the closed position. A sealing ring 33 is then used for the gas-tight closure. This sealing ring may consist, in particular, of an elastomer, a thermoplastic, a metal, etc., and may have a shape adapted to the shape of the plate (e.g. an O-ring) or may be vulcanized to the plate.

[0061] The seal ring can be located on plate 32 (as shown here) or may be located on seal surface 24 (as in other embodiments).

[0062] Furthermore, the adjusting device 3 has a pneumatic drive cylinder 35 that exerts an opening force acting against the preload force and thus provides the opening movement of the valve plate 32. In the illustrated embodiment, the drive cylinder 35 has two pistons 36a and 36b. At least one of the pistons 36a and 36b or the piston 36a is coupled to the adjusting unit 31, so that application of pressure to the drive cylinder 35 can cause the opening movement of the adjusting unit 31.

[0063] In the illustrated embodiment, the preload element 34 cooperates with the piston 36a to urge the piston 36a in the closing direction S.

[0064] Pressure application to the drive cylinders or pistons 36a and 36b can be provided by two compressed air outlets 39a and 39b (respectively) connected to external pneumatic valves.

[0065] The present invention also relates to embodiments of the drive cylinder 35 with only one piston or with three or more pistons (not shown), where the piston assembly is provided to open the valve upon application of pressure.

[0066] The gas inlet valve 1 further comprises a flexible sealing element 25, which in the illustrated example is configured as a diaphragm, in particular as a metal diaphragm, which is fastened to the gas flow unit 2 and to the regulating unit 31 and thereby seals the internal volume 23.

[0067] The diaphragm 25, which is configured as a flexible sealing element, provides a flexible sealing of the internal volume for the regulating device 3. For this purpose, the diaphragm 25 is connected on the one hand to the gas flow unit 2 and on the other hand to the regulating unit, in this case the plate 32 or rod.

[0068] The adjusting device 3 has a limiting element 37 which provides a stop point 38 which limits the adjustability of the adjusting unit 31 along the adjustment axis V in the opening direction O. In this embodiment, the limiting element 37 is shaped and supported in such a way that by manipulating the limiting element 37 the position of the stop point 38 can be changed along the adjustment axis V. The position of the stop point 38 defines the maximum valve opening or valve stroke.

[0069] The stop point 38 is provided in particular by the lower surface or lower edge of the limiting element 37 .

[0070] Manipulation of the limiting element 37 can be understood in the context of the present invention to mean in particular the translation, displacement, rotation, etc. of the limiting element 37 .

[0071] In the illustrated embodiment, the gas inlet valve 1 is shown in the open position, where the piston 36a is in contact with the limiting element 37, in particular with the underside of the limiting element 37, and is therefore unable to move any further in the opening direction O. The coupling or connection between the adjusting unit 31 and the piston 36a thus limits the adjustment of the adjusting unit 31 or the valve plate 32 accordingly.

[0072] The gas inlet valve 1 further comprises a motor 40. The motor 40 can be configured as a drive 40, for example, as an electric motor, a servo motor, or a step motor. The operation of the motor 40 can be controlled, in particular, by a control processing unit 50. For example, a specific number of motor rotations and their direction can be controlled. In this case, the motor 40 should not be understood as a drive or drive cylinder that performs the valve movement (opening and closing).

[0073] The motor 40 is connected to the limiting element 37. In the illustrated embodiment, a connecting element 41 is provided, which is connected to the limiting element 37 by a pin on its underside. The connecting element 41 is configured as a transmission in the illustrated example. Here, the pin resides in a corresponding recess in the limiting element 37 and is locked by a screw fixation. The pin is here clamped in the recess by a screw 42.

[0074] The connecting element 41 is connected at its upper surface to the motor 40, in particular to a motor shaft 43 of the motor 40. The motor shaft 43 engages in a recess in the connecting element 41. The motor shaft 43 may have an external thread here, and the recess in the connecting element 41 may have an internal thread that corresponds to and cooperates with the external thread. The connecting element 41 is arranged, at least for the most part, non-rotatably relative to the motor 40. The motor shaft 43 may be shaped at least in part as a threaded rod or spindle.

[0075] The combined arrangement of the motor 40, the connecting element 41 and the limiting element 37 allows the limiting element to be displaced along the adjustment axis V by operating the motor 40, i.e. by rotating the motor shaft 43. This allows the position of the stop point 38 along the adjustment axis V to be changed.

[0076] In an alternative embodiment (not shown here), the connecting element 41 and the limiting element 37 may be integrally formed, or the limiting element 37 may be directly coupled to the motor 40. Alternatively, the connecting element 41 and the limiting element 37 may be glued, welded, or soldered in another manner known to those skilled in the art.

[0077] The gas inlet valve 1 further comprises a retaining element 45, by which the motor 40 is held. The motor 40 can be screwed onto the retaining element 45, for example. In an alternative embodiment (not shown), the motor 40 can also be integrated into the regulating device 3 or into the valve casing.

[0078] The gas inlet 21 and gas outlet 22 may be provided with respective connections through which conduits to a gas source and a vacuum process chamber can be connected.

[0079] 3 shows in detail the gas distribution unit 2, in particular the adjustable plate 32 in the gas distribution unit 2, and the flexible sealing element 25 which, in the illustrated embodiment, is clamped between the gas distribution unit 2 and the regulating device 3 or between the gas distribution unit 2 and the converter element 10. The clamping here can be provided, for example, by screw fastening.

[0080] The installation of the flexible sealing element 25 in the adjusting unit 31 can likewise be carried out by means of a clamp. Those skilled in the art are aware of the filling of such structural means for connecting the sealing element with the adjusting unit, whereby the plate is adjustably maintained within the internal volume 23.

[0081] The control processing unit 50 has an adjustment function for adjusting the position of the stop point 38 by controlled operation of the motor 40. For this purpose, reference information, such as a target pressure, a target temperature, a target flow rate, etc., is processed and compared with corresponding actual information. Based on the result of the comparison (adjustment information), for example, on the deviation of the actual value from the target value derived from the comparison, the limiting element 37 can be adjusted by a corresponding interval, so that the position of the stop point 38 can be adjusted accordingly.

[0082] For example, the flow rate through the valve 1 can be measured in the open position and the maximum valve opening cross section can be adjusted accordingly in the event of any deviation from the target flow rate. Instead of a direct measurement of the flow rate, the density and / or temperature or pressure or differential pressure of the fluid can be determined and from the respectively measured values ​​the fluid flow rate for that fluid can be estimated and in particular the actual fluid flow rate can be calculated on the basis of said values.

[0083] Additionally or alternatively, the control and processing unit 50 can have a compensation function for compensating for position drift from the target position, whereby it can first be checked whether a position drift exists, for example in the limiting element (37) of the adjusting unit 31 or in the stop of the piston 36, for example by external position determination relative to the plate 32 or by flow measurement in the open position.

[0084] If a position drift is identified, the characteristics of the drift, particularly its magnitude and / or direction, can be determined, and based on the determined characteristics, the position of the stop point can then be adjusted accordingly, particularly changed to provide a desired target position in the open position.

[0085] The control processing unit 50 is also connected, inter alia, to the pneumatic valves and is able to provide open-loop control of the opening and closing of the gas inlet valves.

[0086] A further advantage of the gas inlet valve according to the invention is that stored gas can be collected, so to speak, in a first partial volume which has free access to the gas inlet 21, and which can then be transferred in a flow-technically advantageous manner and suddenly to a second partial volume connected to the gas outlet when the gas inlet valve 1 is opened. Among these flow-technical advantages, the gas inlet valve according to the invention also has very small constructional dimensions.

[0087] The figures always show the plate 32 with an axial upper and lower part (hollow shaft part). In another embodiment, the plate 32 can be a single plate, in which the upper and lower parts of the plate 32 can be replaced by a simple hollow shaft axially sealed against the plate. Furthermore, the figures always show the plate 32 open in the gas flow direction, i.e., adjusted from top to bottom according to the figures. However, in another embodiment, the components involved can be designed and arranged so that the plate is pressed from above against the sealing surface in the closed position and moves upward in the open position.

[0088] Although the present invention has been described based on its preferred embodiments, many other modifications and changes can be made without departing from the scope of the invention. It is therefore intended in the appended claims to cover such modifications and changes as fall within the true scope of the invention.

Claims

1. A gas inlet valve (1) for allowing controlled entry of fluid into a vacuum process chamber, said gas inlet valve (1) comprising: a gas flow unit (2) comprising a gas inlet (21), a gas outlet (22), and an internal volume (23) connecting the gas inlet (21) and the gas outlet (22), the internal volume (23) having a sealing surface (24); a regulating device (3) comprising an adjusting unit (31), the adjusting unit (31) extending into the internal volume (23) and adjustably supported along an adjustment axis outside the gas flow unit (2) in the regulating device (3), the adjusting unit (31) having a valve plate (32) arranged in the internal volume (23), the valve plate (32) being movable by the regulating device (3) to a closed position in a closing direction (S), in which the valve plate (32) rests on the sealing surface (24) and thus prevents gas flow, and the valve plate being movable by the regulating device (3) to an open position in an opening direction (O), in which the valve plate (32) is spaced from the sealing surface (24) and allows gas flow; a flexible sealing element (25) fixed to the gas flow unit (2) and the regulating unit (31) for sealing the regulating device (3) from the internal volume (23); It has The adjusting device (3) has a pneumatic drive cylinder (35) with at least one piston (36a), the piston (36a) being connected to the adjusting unit (31), and an opening force in the opening direction (O) can be generated by applying pressure to the drive cylinder (35). In the gas inlet valve (1), the adjusting device (3) has a limiting element (37) which provides a stop point (38) that limits the adjustability of the adjusting unit (31) along the adjustment axis (V) in the opening direction (O), The limiting element (37) is shaped and supported in such a way that the position of the stop point (38) along the adjustment axis (V) can be changed by manipulating the limiting element (37), and the position of the stop point (38) defines the maximum valve opening. A gas inlet valve (1).

2. the adjusting device (3) comprises a preload element (34) arranged to provide a preload force pressing the valve plate (32) in the closing direction (S) and cooperating with the adjusting unit (31); By applying pressure to the drive cylinder (35), an opening force can be generated in the opening direction (O) which acts against the preload force. A gas inlet valve (1) according to claim 1.

3. 3. The gas inlet valve (1) according to claim 1 or 2, wherein the gas inlet valve (1) has an open-loop controllable drive (40), the drive (40) being connected or coupled to the limiting element (37) in such a way that the position of the stop point (38) can be changed by the drive (40).

4. 4. The gas inlet valve (1) according to claim 3, wherein the drive (40) is configured as an electric motor, in particular a step motor, or as a piezo element, or as an actuator based on magnetic bearings.

5. 5. The gas inlet valve (1) according to claim 3 or 4, characterized in that the gas inlet valve (1) comprises a control processing unit (50) configured to control the driving device (40).

6. The control processing unit (50) has an adjustment function for adjusting the position of the stop point (38), and when the adjustment function is executed, the adjustment function: processing the reference information; processing the actual information; comparing the reference information with the actual information; deriving adjustment information based on the comparison; adjusting, particularly automatically, the position of the stop point based on the adjustment information; The gas inlet valve (1) according to claim 5, configured to perform the following:

7. 7. A gas inlet valve (1) according to claim 6, wherein the actual information comprises information on fluid properties, in particular on the composition, kind or type of fluid, and the reference information provides a correspondence of fluid properties to each position of the stop point.

8. 8. A gas inlet valve (1) according to claim 6 or 7, wherein the reference information comprises information about a target pressure of the fluid and the actual information indicates the fluid pressure at that time, in particular the gas inlet valve (1) is provided with at least one pressure sensor for determining the fluid pressure.

9. 9. A gas inlet valve (1) according to claim 6, wherein the reference information comprises information about a target temperature of the fluid and the actual information indicates the fluid temperature at that time, in particular the gas inlet valve (1) is provided with a temperature sensor for determining the fluid temperature.

10. A gas inlet valve (1) according to any one of claims 6 to 9, wherein the reference information comprises information about a target flow coefficient of the fluid and the actual information indicates the current fluid flow coefficient, in particular the gas inlet valve (1) is provided with a flow measuring unit for determining the fluid flow coefficient.

11. 11. A gas inlet valve (1) according to any one of claims 6 to 10, wherein the reference information comprises information on a target flow coefficient and the actual information indicates the density and / or temperature or differential pressure of the fluid, and in particular the density and / or temperature of the fluid and / or the differential pressure can be used to derive the fluid flow coefficient of the fluid as the actual information.

12. The control processing unit has a compensation function for compensating for position drift from a target position, the compensation function performing the following steps when the compensation function is executed: checking for the presence of position drift; If a position drift exists, determining or deriving characteristics of the position drift, in particular the magnitude and / or direction; and - following the position of the stop point by varying the position of the stop point so as to provide a target position, in particular in the open position; 12. The gas inlet valve (1) according to any one of claims 5 to 11, wherein the following is performed:

13. 13. The gas inlet valve (1) according to claim 12, wherein the position drift is a position deviation of the valve plate (32) or the stop point (38) in the open position relative to a target position for the valve plate or a target position for the stop point, respectively.

14. The step of checking for the presence of position drift or determining characteristics of the position drift comprises: Using position or flow measurement, by determining the temperature of the gas inlet valve; or based on the number of opening cycles performed by the gas inlet valve; 14. The gas inlet valve (1) according to claim 12 or 13, wherein the valve is adapted to

15. the pneumatic drive cylinder (35) has separate pistons (36b), each piston (36a, 36b) defining a respective drive internal volume; each of the drive internal volumes is connected to a respective compressed air passage, and the compressed air passages are arranged such that pressure applied to the drive internal volumes through the compressed air passages causes each piston (36a, 36b) to be adjustable in the opening direction (O), thereby moving the valve plate (32) to the open position; Gas inlet valve (1) according to any one of claims 1 to 14.

16. 16. The gas inlet valve (1) according to claim 1, wherein the sealing surface (24), the valve plate (32) and the sealing element (25) have a circular cross section, the internal volume (23) is at least partially cylindrical, and the sealing surface is formed by a step in the internal volume.

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